This invention relates to hangers or clips attached to the metal lattice supports of suspended ceilings, such that various signs or objects can be suspended from the hangers.
Metal hangers are generally used for the purpose of hanging signs, advertising material, or other materials from a suspended ceiling. This is usually done by attaching a string or wire to the metal hanger and then tying the sign to the string. Previously this process required that a person who is hanging the sign obtain a ladder sufficiently high so as to allow him to reach the metal strips or supports in the suspended ceiling. Then, while the person is standing on top of the ladder, he has to fasten the metal or plastic hanger to the metal grid work which supports the ceiling tiles. This procedure is precarious and inherently dangerous to the installer.
Placement of the ladder in the aisle to accomplish this task causes interference with customer usage of the aisle. It also presents a risk to customers or employees who may be in the vicinity of the ladder. Such personnel can be hit by falling tools, or implements of the installation or of the sign itself. Furthermore, the installer himself may fall from the ladder which may cause injury to himself and others in the aisle.
This previous installation process required the installer to gather all the tools necessary for the installation, placement of warning signs around the ladder so that customers do not come directly under the ladder, performing the installation task, and then replacing all tools and the ladder. The installation of just one or two hangers required a considerable amount of time and effort in addition to placing the installer and customers at risk of injury.
Several types of hangers or clips have been used in the past. For example, in U.S. Pat. No. 3,612,461 there is illustrated a clip which closely fits about opposite sides of an inverted T-shaped grid member of a suspended ceiling. One end of the clip is supported by a wire connected to the building structure and the other end of the clip is attached to a light fixture or other device to be supported. This clip is not easily installed nor is it retained in place by the ceiling panels such as applicant's device described herein operates.
Other clips or supporting devices are illustrated in U.S. Pat. Nos. 4,318,525; 4,323,215, and 4,075,750. All of these devices have a clip portion or winged member which engages the cross-bar of the inverted T-shaped ceiling support member. In each of these patents, the clip is held in place merely by frictionally engaging the upper and lower faces of this inverted T-shaped member. The ceiling panels do not play any role in locking or retaining the clip.
A light duty clip manufactured of a single length of wire is illustrated in U.S. Pat. No. 3,936,913. A shortcoming of this device is that it is only designed for mounting on an inverted T-bar located away from the corner or walls of a room and is not usable for mounting the clip adjacent to a wall. Furthermore, the design of this clip is such that the upstanding wires engaging the edges of the panel would tend to dig into the panel edges which would permit the clip to rotate. This would further destroy the panel edges which may ultimately result in the failure of the clip.